New sensor detects biological pathogens in tiny doses

When the first real threat of biological warfare was heralded during the 1991 Persian Gulf War, dozens of pathogens went undetected, mostly because of the limited technology available to the military.

To detect many of these weaponizable biological agents (WBA), a sensor must be able to identify a pathogen at a measurement of parts per trillion. Technology available only allowed measurements to the parts per billion.

A novel sensor, developed by two Virginia Tech engineering faculty members, is now capable of literally identifying "a needle in a haystack," showing results 20 times more powerful than previous sensing devices.

William Velander, a biochemical engineer who heads Virginia Tech's Pharmaceutical Engineering Institute, teamed with electrical engineer Kent Murphy, a fiber optics expert, to develop the prototype biosensor.

Velander adapted a technology he invented that is employed to purify pharmaceuticals present in blood plasma at trace levels. By combining his scientific process with an optical fiber sensing device, Velander and Murphy have found that they can "capture biological warfare agents" that were previously undetectable.

Velander estimates that several hundred deadly WBAs that currently exist can now be detected.

Another advantage of the new sensor is its speed. Current technology for detecting certain pathogens typically requires at least an hour of laboratory based effort. This new biosensor produces its finding in just a few seconds.

Velander's partner, Murphy, is also the president of Virginia's fastest growing technology company, FandS Inc. The Blacksburg-based company funded the work, and it now plans to market the new technology through a second company called Luna.

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Biotech solution devised for feral cat population

A student in the Virginia-Maryland Regional College of Veterinary Medicine has developed a genetically engineered bacterium to serve as an oral contraceptive that may help solve a feral-cat overpopulation problem.

About 30 to 60 million stray cats roam the United States, says second-year student Michelle Meister-Weisbarth. These feral cats are wreaking havoc on the nation's songbird population and possibly spreading disease and altering ecological balances.

Working with faculty mentor Dr. Stephen Boyle in the Virginia-Maryland Regional College of Veterinary Medicine's Center for Molecular Medicine and Infectious Disease, Weisbarth conducted research which suggests the viability of a new immuno-contraceptive approach for controlling reproduction in these feral cats.

The method uses genetic engineering to modify a well-tested strain of bacterium, Salmonella (that can no longer cause disease), making it function as a contraceptive. Meister-Weisbarth introduced into the Salmonella gene from a swine egg. Antibodies that develop against this substance block the ability of a sperm to fertilize the egg by occupying sperm receptor sites on the egg. The vaccine strain could be delivered to feral cats in food bait.

The Salmonella bacterium is especially useful as a vehicle for delivering an immuno-contraceptive agent because it survives in the animal's stomach after ingestion and crosses the intestinal tract to cells in the immune system. As this bacterium is killed, it releases an antigen that produces the antibodies that block fertilization.

Meister-Weisbarth used a summer fellowship grant from the Geraldine R. Dodge Foundation to develop the genetically engineered contraceptive. She and Boyle are seeking funding to test the attenuated Salmonella contraceptive vaccine in cats.

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